iStock/Thinkstock(WASHINGTON) -- The White House is prepared for a long battle to pass tax reform this fall after setting an "aggressive schedule,” an official said on Monday.

"We're in for a long fall," White House Director of Legislative Affairs Marc Short said of Congress during a panel Monday with Treasury Secretary Steve Mnuchin, led by Americans for Prosperity President Tim Phillips in Washington, D.C.

According to Short, the White House hopes for the bulk of tax reform legislation to be drafted and written up by August, so the markup process of the bill can begin in the House after Labor Day. Short said they believe markups and hearings in the Senate finance committee will begin at roughly the same time.

The White House expects to have the bill through the House by October and passed in the Senate by November.

"That, I think, is an aggressive schedule, but that is our timetable," Short said, later adding, "Hopefully we'll have completion by mid-November."

According to Mnuchin, he and White House economic adviser Gary Cohn have been meeting with House and Senate leadership since January and have over 100 Treasury Department staffers working on tax reform.

Mnuchin said they are “very proud of the fact" that they're on the same page so far with the House and Senate on the fundamentals of the tax reform plan.

"We didn't want to have three different plans. We wanted to have one plan," he said.

Mnuchin argued that, "This is critical to getting this done and it's going to get done this year."

Short also argued that tax reform can be bipartisan, and said that they've engaged many Democrats in the conversation.

"So far, initial conversations have been very encouraging," Short said.

Mnuchin and Short are pushing for tax reform to be passed through regular order, instead of the reconciliation process, which would allow the bill to pass with a simple majority of 51 votes.

"It's important that people feel they have their input and this is a complicated issue, and although we've agreed on the principles and we've agreed on fundamentals, there's lots and lots of details," Mnuchin said. "We respect the process in the House and the Senate and the committees to get that done. But again, this is about everybody's on the same page on moving this forward… for a once-in-a-decade opportunity."

"We will have success," Mnuchin said. "This is a pass-fail exercise. And we will pass tax reform."

Mnuchin also argued that President Trump is ready for the brewing battle over tax reform.

"This is the greatest negotiator," Mnuchin said of Trump. "He understands business. He understands it. He's going to be on the road helping us selling it."

Despite acknowledging the tough path ahead, Mnuchin and Short both seemed confident that the administration can pass tax reform.

"There's a lot of work that's been done. There's more work to do," Mnuchin said. "But we feel like we've made a lot of progress and we're going to get this over the goal line."